[openstreetmap/openstreetmap-website] Add OpenMapTiles vector map (PR #4042)
Brian Sperlongano
notifications at github.com
Sat May 27 12:59:38 UTC 2023
> Maplibre doesn't support some scripts (e.g. Burmese, Lao, and other Brahmic scripts), so it can't display the local name.
That's not _exactly_ accurate. The issue is that MapLibre doesn't support ligatures and combining characters correctly, and instead displays them anywhere from slightly to terribly wrongly. However, OSM-Carto also renders some of these scripts wrongly as the examples below will show (and should probably be documented if they're not already). Whether the "wrong" rendering makes the label unreadable or just slightly off will depend heavily on the script involved, and in my experience, it's the worst in Right-to-Left scripts.
This is what MapLibre displays for the United States label, in Lao:
[](https://zelonewolf.github.io/openstreetmap-americana/#map=4/33.24/-96.49&language=lo)
However, it is supposed to look like this:
[](https://lo.wikipedia.org/wiki/%E0%BA%AA%E0%BA%B0%E0%BA%AB%E0%BA%B0%E0%BA%A5%E0%BA%B1%E0%BA%94)
The issue is that the squiggly line above the second-to-last character is supposed to be directly over it, not off to one side. This issue is pervasive across all ligature/combiner scripts. While a Lao reader might still understand the script above, it would definitely look wrong, and this problem in other scripts results in mangled text that's absolutely unreadable to native speakers.
This is something which has _always_ been broken in mapbox-gl and is a high priority for maplibre-gl to get right, and it's documented in maplibre/maplibre#193.
Examples of rendering the Lao capital of Vientiane, which should appear in local script as:
### ວຽງຈັນ
Google Maps:
[](https://www.google.com/maps/@17.9637196,102.6238214,13z?entry=ttu)
OSM Americana (based on MapLibre):
[](https://zelonewolf.github.io/openstreetmap-americana/#map=10.92/17.9901/102.6201)
OSM Carto:
However, looking at these examples, it seems that osm-carto isn't actually any different from what MapLibre is producing.
Let's take a look at Kathmandu, Nepal, which is supposed to appear as:
### काठमाडौँ
Google Maps:
[](https://www.google.com/maps/@27.7089543,85.2849333,13z?entry=ttu)
OSM Americana
[](https://zelonewolf.github.io/openstreetmap-americana/#map=11/27.6802/85.3489&language=en)
OSM Carto:
[[](https://www.openstreetmap.org/#map=12/27.6858/85.2797)](https://www.openstreetmap.org/#map=11/17.9902/102.6817)
Mandalay, Burma, perhaps?
Should be:
### မန္တလေး
Google Maps:
[](https://www.google.com/maps/@21.9579896,96.0893805,13z?entry=ttu)
OSM Americana:
[](https://zelonewolf.github.io/openstreetmap-americana/#map=11/21.9869/96.12&language=en)
OSM Carto:
[](https://www.openstreetmap.org/#map=11/21.9816/95.9621)
Burmese is where we really start to see the problem, with that infinity-sign looking diacritic that's supposed to be under the second character coming in rather mangled. However, OSM-Carto also gets it slightly wrong by jamming the ligature up into the character when there's supposed to be space between them.
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